1. Field of the Invention
The present invention relates to a video signal processing device and a method of processing gradation of brightness, and more particularly, to a video signal processing device capable of improving the contrast ratio and of improving the user satisfaction of a plasma display device, and to a method of processing gradations of brightness.
2. Discussion of the Related Art
Display devices are widely used as output device for delivering representations of video information to an audience, and the display devices may be broadcasting terminals as well as computer terminals. Recently, flat panel displays (FPD) such as liquid crystal displays (LCD), field emission displays (FED), and plasma display devices are rapidly becoming ubiquitous.
Among the various display devices, plasma display panels (PDP) have higher brightness and emission efficiency, and a wider view angle compared to the other FPDs. Therefore, the PDPs, used as large size display devices, are spotlighted as the display devices which are replacing contemporary cathode ray tubes (CRT).
A user who views the images displayed on a display device may have several view patterns. For example, since the user looks at the center of a screen of the display device, the user is satisfied when the brightness of the center of the screen is high. When the user views a moving image displayed on the display device, however, because the range of view of the user is narrower for the moving image compared to a still image, the user is insensitive to a fine difference in brightness. Here, when the user views the moving picture on the screen, the user looks at a moving object.
In the case of contemporary plasma display devices, however, since the brightness condition of the still image is commonly applied to the moving picture, even though the view pattern of the user varies with the still image and the moving picture, a gradation of the brightness that is most appropriate to the view pattern of the user cannot be displayed. Therefore, contemporary plasma display devices are unable to satisfy the viewing satisfaction of the user.